This invention relates to flow control devices and, more particularly, to a compact, regulated gas flow control valve.
The invention is particularly concerned with controlling the flow of oxygen from oxygen cylinders wherein oxygen is stored at extremely high pressures such as 500-2000 p.s.i.g., there being a requirement to deliver oxygen from such source at a desired, constant flow rate as dictated by medical requirements, such as for emergency treatment, and for hospital, clinical and other usages. Accordingly, it may be required to deliver oxygen at a flow rate which may vary from very little, such as as low as 0.25 liters per minute, up to approximately 15 liters per minute. It is, therefore, desired to provide not only the function of reducing the high pressure to a regulated substantially constant delivery pressure, but also to allow ready preselection of a desired flow rate.
Medical professionals in institutions or other users of such equipment may have different preferences as to the minimum and maximum volumetric flow rates which such apparatus should provide. Further, different users are expected to have different preferences as to the available sequence of flow rates.
For example, one user may prefer a control sequence of 0.5, 0.75, 1, 1.5, 2, 3.5, etc., liters per minute; whereas another user may prefer a sequence of 1, 2, 4, 6, 8, etc., liters per minute, so that the design of such apparatus is rendered difficult for all intended modes of usage. Although the use of vernier controls allowing infinite adjustments of flow rates has been proposed, in medical usage it is preferred to be able to positively and rapidly allow selection only according to such a preferred sequence, thereby assuring rapid, error reducing selection, as required in prompt emergency treatment and with only definite, defined control positions being available thereby to preclude inaccurate settings, inoperative positions, and to obviate close visual monitoring of selections and flow rates.
It is an object of the present invention to provide a compact, regulated gas flow control valve of improved, advantageous function and design.
It is a further object of the invention to provide such an improved flow control valve which is particularly intended for controlling the flow control of oxygen delivered from a high pressure oxygen cylinder.
It is a further object of the invention to provide such a gas flow control valve which accurately and reliably drops such high pressure to a substantially constant, regulated delivery pressure and which allows selection of a precalibrated flow rate of oxygen from said constant delivery pressure only according to a preferred schedule of delivery rates.
Additionally, it is an object of the invention to provide such a gas flow control valve which allows definite, positive selection only of a desired one of a plurality of available flow rates, precluding inaccurate or indefinite settings, inoperative selector positions, and eliminating need for close visual monitoring of the control valve or flow rates provided thereby.
Among other objects of the present invention are the provision of a gas flow control valve which is of extremely compact, streamlined and efficient construction, being both reliable and long lasting in usage as well as relatively light in weight; which is rapidly and conveniently securable to a conventional high-pressure oxygen cylinder; which provides facility for rapid emergency connection to receive oxygen directly at a substantially constant delivery pressure without flow control; and which allows for automatic pressure relief operation.
Briefly, a regulated gas flow control valve of the invention includes a single valve body having clamp means at one end for clampingly securing the valve body directly to a source of high pressure gas, such as an oxygen cylinder, there being an inlet for this purpose at one end of the valve body for directly receiving the high pressure gas for such source and admitting the gas to the interior of the valve body. The clamp arrangement causes the body to be tightly maintained in communication with the gas source. Within the valve body, which is of compact configuration, there is a regulator for dropping the high pressure to a low pressure and for maintaining the low pressure substantially constant. The regulator includes a valve seat to which said inlet permits communication of said gas at high pressure. A valve member including a seal is positioned within the valve body for axial movement between closing and opening positions. In the open position, the seal is unseated from the seat to open the inlet and to admit gas at high pressure into an inlet chamber surrounding the valve seat. In the closed condition, the valve member causes the seal to be positioned against said seat to block the inlet and to limit or prevent gas from being admitted to the inlet chamber. As the gas enters the inlet chamber upon opening movement of the valve body, the gas is permitted to expand into the inlet chamber. A piston, also within the valve body, is axially movable therein, being connected to the valve member for corresponding movement thereof in response to piston movement. A compression spring within the valve body resiliently biases the piston in a direction for opening movement of the valve body. A piston chamber is defined, also within the valve body, over the piston head, there being a gas conduit providing communication between the inlet chamber and the piston chamber for admitting low pressure gas to the piston chamber for exerting pressure upon the piston head, and causing the piston to move to a position urging the seal of the valve member against the valve seat to an extent causing pressure within the piston chamber to be maintained at a substantially constant delivery pressure. A rotor is positioned proximate the piston chamber, and is fitted with a plurality of precalibrated orifice means, each configured for receiving the gas at said constant delivery pressure. A selector at one end of the valve body opposite from the inlet is provided for rotating the rotor relative to a gas outlet port for delivery of the gas, such as oxygen, at a precalibrated flow rate determined uniquely by respectively one of the orifice means. A positive detent mechanism assures that the only positions of the rotor may be for completely preventing flow of the gas or permitting flow only through one of the orifice means.
Other objects and features will be in part apparent and in part pointed out hereinbelow.